Motor fuel composition

ABSTRACT

MOTOR FUEL COMPOSITION CONTAINING 2-CHLOROETHYL DIPHENYL PHOSPHATE SURFACE IGNITION SUPPRESSOR.

United States Patent 3,560,174 MOTOR FUEL COMPOSITION Stanley R. Newman,Fishkill, Kenneth L. Dille, Wappingers Falls, and Rodney L. Sung,Fishkill, N.Y., assignors to Texaco Inc., New York, N.Y. No Drawing.Filed Nov. 22, 1967, Ser. No. 684,971 Int. Cl. C011 1/26 US. Cl. 44-69 4Claims ABSTRACT OF THE DISCLOSURE Motor fuel composition containing2-chloroethyl diphenyl phosphate surface ignition suppressor.

This invention relates to a motor fuel composition for spark-ignitedinternal combustion engines. More particularly, this invention relatesto a motor fuel composition having improved surface ignition propertiesbased on a phosphate ester additive.

Organic phosphorus compounds have been proposed for use in motor fuelcompositions for various purposes, such as load-carrying additives,scavengers, surface ignition suppressors and the like, see US.2,291,442, US. 2,889,212 and US. 2,892,691. Despite extensive artdisclosing advantages from the use of organic phosphate additives, theircommercial adoption has been restricted to a few types of phosphoruscompounds largely because of the anti-knock destruction valuesassociated with most phosphorus additives. That these values are high isshown in an article entitled The Effect of Phosphorus Deposit Modifierson Gasoline Octane Quality by Gunderloy and Neblett, which appeared in apaper presented to the Petroleum Chemistry Division of the AmericanChemical Society given at Cleveland, Ohio on April 5-14, 1960, pages 75to 86. On page 85, of this paper, there are examples of organicphosphorus additives, such as tributyl phosphate, dibutyl phosphate andtributyl phosphine, which had anti-knock destruction values ranging from-1.5 to 3.6 as determined by the Motor Octane Number method. When it isrealized that an increase of but 0.1 Motor Octane Number in a modernhigh-octane gasoline is an important and valuable improvement, it isevident that anti-knock destruction values of the order noted areprohibitive.

An organic phosphorus compound additive for gasoline has now beendiscovered which is highly effective for improving the surface ignitionproperties of a high octane gasoline while at the same time exhibitingan unexpectedly low anti-knock destruction value.

In accordance with this invention, there is provided a motor fuelcomposition comprising a mixture of hydrocarbons in a gasoline boilingrange containing from about 0.1 to 1.0 theory of 2-chloroethyl diphenylphosphate. The expression theory as used herein relates to the amount ofphosphorus required to react stoichiometrically with the lead present inthe gasoline to form Pb (PO0 The preferred amount of the surfaceignition suppressor is from 0.2 to 0.5 theory.

The surface ignition additive of the invention is added to a motor fuelin the gasoline boiling range containing an anti-knock amount of analkyllead compound. The motor fuel may consist of any hydrocarbon fuelincluding parafiinic, naphthenic and aromatic hydrocarbons or mixturesthereof, suitable for use in spark-ignited internal-combustion engine.These fuels are obtained from the distillation of crude oil, by thecatalytic or thermal cracking of gas oils, by the alkylation ofisoparaffins with olefins, or by the polymerization of olefins. Theboiling point of the motor fuel or gasoline will generally be in therange from 100 F. to about 400 F. The motor fuel "ice of the inventionwill contain a tetraalkyl lead compound, such as tetraethyl lead ortetramethyl lead, in a concentration ranging from about 0.5 ml. to about4 ml. per gallon of fuel. The motor fuel may also contain a number ofadditives conventionally employed in gasoline, such as anti-oxidants,stabilizers, dyes, and metal suppressors.

A gasoline containing the additive of the invention was tested for itssurface ignition effectiveness in an 11.3/1 compression ratiocylindrical wedge single cylinder engine. The engine was continuouslyrun on the test fuel over a 20-hour test period during which time theengine operation was alternated between a 50-second idle cycle (600rpm.) and a ISO-second full throttle cycle (900 r.p.m.). The surfaceignition count rate was obtained using an ionization gap (spark plug) asa surface ignition pick-up coupled to a recording counter device. Thesurface ignition rate is expressed as the number of counts per hour, thelower the count value the better the surface ignition performance of thefuel.

The tests were conducted using a high octane blended gasoline as thebase motor fuel. This gasoline contained 41% aromatic hydrocarbons,boiled in the range of to 354 F., had a motor octane number of 91.3 andcontained 3 ml. of TEL per gallon. The additive of the invention wasblended into this leaded gasoline to provide the indicated amounts ofphosphorus in theories. The results are the average of three runs.

The base fuel was found to give 190 surface ignition counts per hour.

At a concentration of 0.2 theory 2-chloroethyl diphenyl phosphate in theadditive-containing fuel, this fuel was found to give 145 surfaceignition counts per hour. This performance is a substantial improvementin surface ignition properties as compared to the surface ignitionproperties of the base fuel.

As indicated above, the critical factor which prohibits the use of mostorganic phosphorous compounds in gasoline is the high anti-knock lossescaused by these additives. A surface ignition additive having an AKD(antiknock destruction) value greater than zero requires the addition ofextra tetraethyl lead or other anti-knock additives to bring thegasoline up to its original anti-knock quality, thus imposing a severeeconomic penalty.

The AKD caused by the additive of the invention and by a related organicphosphate was determined using the motor octane number method. The basefuel was a RON premium leaded gasoline containing 3.0 ml. of tetraethyllead and having a motor octane number of 89.4. The organic phosphateadditives were employed at concentrations of 0.2 and 0.4 theories ofphosphorus. The octane determinations were made by an absolute numbermethod in which engine, operator and time variables were controlled byeach set of determinations. Three or more series were averaged andcompared to the base fuel without the phosphorus additive present.

Anti-Knock Destruction Values for Additives by the Motor Octane Method0.2 theory AMON 2-chloroethyl diphenyl phosphate +0.03Tris-2-chloroethyl phosphate 0.5

0.4 theory 2-chloroethyl diphenyl phosphate -0.1 Tris-2-chloroethylphosphate -0.5

It is evident that the anti-knock destruction value of 2-chloroethyldiphenyl phosphate is a vast improvement over that of the otherhalogenated phosphate ester, tris- 2-chloroethyl phosphate.2-chloroethyl diphenyl phosphate is a satisfactory commercial additivefrom the standpoint of the critical anti-knock destruction value as wellas for surface ignition improvement in contrast to the unacceptabletris-2-chloroethyl phosphate.

Obviously, many modifications and variations of the invention, ashereinafter set forth, may be made without 7 departing from the spiritand scope thereof, and therefore, only such limitatons should be imposedas are indicated in the appended claims.

We claim:

1. A motor fuel composition comprising a mixture of hydrocarbons in thegasoline boiling range containing a tetraalkyl lead anti-knock additiveand from about 0.1 to 1 theory of 2-chloroethyl diphenyl phosphate.

2. A motor fuel composition according to claim 1 in which said phosphateis employed in a concentration of 0.2 to 0.5 theory.

3. A motor fuel composition according to claim 1 containing from about0.5 to 4 ml. per gallon of tetraalkyl lead anti-knock agent.

4. A motor fuel composition according to claim 3 containing tetraethyllead.

References Cited UNITED STATES PATENTS 2,892,691 6/1959 Howell, Jr.44-69P l0 PATRICK P. GARVIN, Primary Examiner Y. H. SMITH, AssistantExaminer US. Cl. X.R. 44-69P, 76

